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require 'knapsack_solver/instance'
module KnapsackSolver
# This class represents a set of 0/1 knapsack problem instances.
class Dataset
# Initializes set of 0/1 knapsack problem instances.
#
# @param id [Integer] Dataset ID number.
# @param instances [Array<Instance>] set of the 0/1 knapsack problem instances.
def initialize(id, instances)
@id = id
@instances = instances
end
# Parses set of a 0/1 knapsack problem instances from a character stream.
#
# @param stream [#eof?,#readline,#each_line] character stream holding the dataset.
# @return [Dataset] dataset instance parsed from the stream.
def self.parse(stream)
id = parse_id(stream)
instances = stream.each_line.with_object([]) { |l, o| o << Instance.parse(l) }
raise StandardError, 'dataset: missing instances' if instances.empty?
Dataset.new(id, instances)
end
# Parses ID of a 0/1 knapsack problem dataset from a character stream.
#
# @param stream [#eof?,#readline,#each_line] character stream holding the dataset.
# @return [Integer] dataset ID number.
def self.parse_id(stream)
raise StandardError, 'dataset: missing ID' if stream.eof?
s = stream.readline.split
raise StandardError, 'dataset: first line does not contain ID' if s.size != 1
begin
raise StandardError, 'dataset: ID is negative' if Integer(s.first) < 0
rescue ArgumentError
raise StandardError, 'dataset: ID is not an integer'
end
Integer(s.first)
end
attr_reader :id, :instances
end
end
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